Sankey charts: Unlocking the Flow in Data Visualization and Complex Network Exploration

Data visualization is a powerful tool in communicating complex information and understanding intricate systems. One particularly intriguing and effective visualization technique that stands out in this realm is the Sankey chart. A Sankey diagram, also known as a flow diagram or energy flow diagram, is a graphical representation that visually communicates the flow of values, materials, or data between different entities or categories. This article delves into the world of Sankey charts, exploring their creation, applications, and the story they tell about complex networks.

Introducing the Sankey Chart

The Sankey chart, first introduced by Sir Francis Galton in the late 19th century, is a dual-axis representation that helps viewers trace the cumulative quantity or value of a flow from one entity to another. It elegantly represents flow or transformation processes, whether it’s energy, money, particles, or data. The primary components of a Sankey diagram are:

1. Nodes: Represent the entities or categories involved in the flow. These can be anything from countries to companies, products, or even individual transactions.

2. Straight paths (lines): The Sankey lines connect the nodes, illustrating the amount or value that flows from one to the other. The width or thickness of the line indicates the magnitude of the flow.

3. Arrowheads: They indicate the direction of the flow: towards the receiving node or away from the sending node.

4. Cumulative totals: By showing the total flow at each step (often in a sidebar or graduated scale), the diagram provides a visual understanding of the accumulation through the network.

Creating a Sankey Chart

Creating a Sankey chart in most visualization tools, including Excel, Tableau, D3.js, or any graphic design software, is relatively straightforward. Here’s a basic process to create one:

1. Define the entities and flows: First, organize the data in a table or spreadsheet, with each row representing a flow from one node to another.
2. Assign units, weights, or values: Each row should contain a quantity or value for the flow.
3. Choose appropriate format: Select a data visualization tool that supports Sankey charts, then set up your chart with the proper axis, nodes, and flow lines.
4. Adjust the styling: Customize the appearance of the chart by adjusting line colors, labels, titles, and any other visual elements that enhance readability.
5. Add cumulative totals: If necessary, plot cumulative values in a separate graph or as a side axis.

Applications of Sankey Charts

The versatility of Sankey charts makes them a valuable tool in various domains. Some common applications include:

1. Resource allocation: In industries, Sankey charts can represent the distribution of resources (such as energy or materials) among processes or facilities.

2. Transport and logistics: In supply chains, they effectively illustrate the movement of goods and materials from suppliers to consumers.

3. Economic flows: This format can display financial transactions or investment profiles, showing the inflows, outflows, and net changes.

4. Policy analysis: Sankey maps are used to visualize policies, such as grants or subsidies, and their distribution across targeted groups or regions.

5. Risk assessment: In risk management, they can show the flow of potential hazards or failures through a system.

6. Education and decision making: They facilitate understanding of complex systems, fostering better communication and decision-making.

Conclusion

Sankey charts are a powerful visualization technique that unravels the intricate flow of data in complex networks. By creating a visual story, they make complex information accessible and easy to understand, enhancing insights in various fields. Whether you’re a data analyst, a policy expert, or simply trying to grasp the intricate workings of a process, Sankey diagrams are a valuable addition to your visualization repertoire.

SankeyMaster

SankeyMaster is your go-to tool for creating complex Sankey charts . Easily enter data and create Sankey charts that accurately reveal intricate data relationships.